1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to an apparatus and method for selecting the best beam in a wireless communication system which is performing beam forming
2. Description of the Related Art
To meet the ever-increasing demand for wireless data traffic, a wireless communication system is being developed to support a higher data transmission rate. To increase a data transmission rate, a 4th-Generation (4G) system that is now being commercialization pursued technology development mainly to improve spectral efficiency. However, it has become difficult to meet the explosively increasing demand of wireless data traffic with only the spectral efficiency improvement technology.
A way for solving the above problem is using a very wide frequency band. A frequency band presently used in a mobile communication cellular system is generally 10 Giga Hertz (GHz) or less, and there is a great difficulty in securing a wide frequency band. Accordingly, there is a need to secure a broadband frequency at a higher frequency band. However, as a frequency for wireless communication increases, a propagation path loss increases. Due to this, a wave reach distance becomes relatively short, thereby causing a decrease of service coverage. One technology for solving this (i.e., for decreasing the propagation path loss to increase the wave reach distance) is a beamforming technology.
The beamforming can be divided into transmit beamforming and receive beamforming. The transmit beamforming generally concentrates wave reach coverage on a specific direction using a plurality of antennas. Generally, a form of gathering the plurality of antennas is called an antenna array, and an individual antenna included in the antenna array is called an array element. If the transmit beamforming is applied, a signal transmission distance increases and simultaneously, a signal is concentrated in an intended direction (e.g., a signal is almost not transmitted in directions other than an intended direction). Accordingly, there is an advantage in which interference in other users greatly decreases. The receive beamforming concentrates wave reception on a specific direction using a reception antenna array at reception side. Consequently, the sensitivity of a signal received in an intended direction is increased and, by excluding a signal coming in directions other than the intended direction, an interfering signal is cut off.
As described above, the introduction of a very high frequency (i.e., millimeter (mm)) wave system is expected to secure a wide frequency band. In this case, to overcome a propagation path loss, a beamforming technology is being taken into consideration. Accordingly, there should be proposed an alternative for effectively performing beamforming under a mobile communication environment in which users travel and a propagation environment changes.
Therefore, a need exists for an apparatus and method for performing effective beamforming in a wireless communication system. In addition, a need exists for an alternative for decreasing a system overhead and simultaneously obtaining a sufficient antenna gain suitably using various beam patterns.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.